End connection for tubular lamps



June 16, 1953* J. w. EASTER 2,642,521

END CONNECTION FOR TUBULAR LAMPS Filed lay 17, 1950 N 2 Sheets-Sheet 1 INVE N TOR o/m W/Y/I'am E a; fer

June 16, 1953 J. w. EASTER 2,642,521

END CONNECTION FOR TUBULAR LAMPS Filed May 17, 1950 2 Sheets-Sheet 2 dohn Wil/iamfaszer INVENTOR Patented June 16,

2, 42,521 7' END CONNECTION roa TUBULAR LAMPS John William Easter, Acton, London, England,

assignor to Ozalid Company Limited, London, England, aBritish company Y Y Application May 17,1950, Serial No. 162,551

InGreat Britain May .26, 1949; 7

This invention relates to the external end connections and supports for electric lamps; of v the elongated tubular type (such for example as are used in association with the printing cylinder or bend. of a photo-copying machine) comprising a transparent or translucent vitreous envelope at'opposite ends of which leading-in Wires, fused to the wall of the envelope, extend outwardly therefrom. In this type of lamp the envelope may contain a continuous filament, or in the case of a gas discharge lamp there may be an electrode at each end of an envelope containing a gas or vapour, a high voltage being applied across the electrodes'to create an electrical discharge through the gas or vapour. In gas discharge lamps of the type described, the leading- 3 Claims: (01. zit-114i .f

.eration al sleeve ,of heat-resisting electricallyinsulating material located, within. the .sec ondmentioned partof the housing and pmyiding'ja air-space enclosure '.within which "ther'a foresar leading-in wire is freely accommodated, ,and' plug-and-socket coupling comprising an insulat-f ing holder detachably connected tothesecond mentioned part of the housing and a' contact ele'- ment carried by the holder and electrically con-I l nected to the leading-in wire aforesaid. f I,

In one arrangement according to theinven- U tion the outside fwallfof' the faforesaidpart of; the housing 'surroundingtheleadingeinwire formed with a flat to which is attached, inv a di rection at right anglesto the bore of the hous 4 ing, the insulating holder which as aforesaid ear;

in wires are usually protected by means of glass or porcelain beads threaded on the wires, but.

if the lamp isdisturbed, there is a possibility of a leading-in wire protrudingbetween adjacent beads and giving riseto a Short circuit or injury to the operator. Moreover inlamps of the type 7 described, considerable heat is generated when the lamp is in operation and hitherto the provision made for the consequent expansion of the One object of the present invention is to pro-- vide an external'end connection and support for tubular lamps of the type describedjwhe'rein the risk of short circuiting is minimised.

=proved manner may readily be coupled with. and

uncoupled from-the source of electrical supply.

' A further object of the invention is to provide an'external end connection and support :for tubular lamps of the type described in which, in an improved manner, the lamp is free to expand during operation. J

According to this invention there is provided, for use in combination with an electric lamp of the type described having atransparent vitreous envelope at opposite ends o'f which leading-in wires, fused to the wall of the envelope, extend outwardly therefrom, an external end-connection and support for the lamp comprising an elongated tubular metal housing having one end part'surrounding the body portion of the lamp atthe end thereof and an opposite end part surrounding. the corresponding leading-in wire, a ring-like circumferentially expansible clamp secured to the housing within thefirst-mentioned part thereof and shaped to surround and en:

gage the vitreous envelope of. thelarnp providing forits free "circumferential expansion during opries a contact element of the plug-and-socket coupling. I g

Preferably, the aforesaid part of the housing 2 Q. surrounding the leading-in", wire is stepped down in diameter and" eceentrically disposed inrela tion to the otherpart of the housing, an inter nal flange being formed at the'junction between the two hou'singparts, and the aforesaidring like expansible clamp being secured to saidflange j The foregoing and other features of theinven-jj tion are embodied in an example which will now 1., be described with reference'to the accompanyingijj drawings, in which:

Figure 1 is an end view of the end con and Sup ort for the lamp; a

Figure 2 is a cross section at the line 2-2 of ection Figure 1; p

Figure 3 is a cross section at the line 3-3015 Fie re2; j J g o Figure 4 is a cross section at the line 4-45;

Figure2; and

bular housing fabricated in light alloyiand'com.

prising two parts 10,. l'l,,-"whereof -the',part, l'l is' steppeddownin diameter and isflec'centrically disposed in relation to the part lo-(as'shownin Figure 2). The part I I of the housing isformed, with an integrallongitudinal ill 12, slottedat I3, for the convenient attachment of the house e ing to the framework of the apparatus. At .1

position where the housing isfstepped down in, -l

diameter, an annular rib I4 is formed, an,d tothis rib there attached, by means of screws J5, flanged arms lfic integ'ralwith a split cylindri- 'cal sleeve ll. The'endof a gas dischargelamp" I! is supported by the split sleeve 11 at a position spaced inwardly from the leading-in wire I9 associated with that end of the lamp. An asbestos packing is interposed between the sleeve l1 and the external wall ofthe lamp. Cone siderable heat is developed during operation ofthe lamp and the flexible mounting just described provides a satisfactory way of allowing for expansion of the lamp envelope.

Within the part in of the housing: I0, Ii, a metal bush 2| (conveniently of nickel) is located and held in place by means ofa grub screw 22'. The bush 2| is arranged to support a glass tube 23 enclosing the gas discharge lamp i8 and serving as a restriction filter for light rays having a harmful physiological effect. The end of the tube 23 is arranged to abut against a flange 24 on the bush 2 I, and theetube is further located by means of longitudinally extending strips 25 anchored by screws 26 to the end portion in of the'housing and carrying pins 21, arranged to engage in apertures in the glass tube. In Fig ure2for convenience of illustrationa retaining strip 25 has been shown out of its proper angular setting.

Within the smaller diameter portion ll of the housing a lining tube 28 of'porcelain is located. The end of the lamp is arranged to extend (as shown in Figure 2) into the interior of the porcelain tube 23 through an opening 29. The end of the part ii of the housing is closed by a plate 33 offibrous insulating material secured to the housing by screws 31. The external wall of the part I I of the housing is formedv (as shown in Figure 4) with a flat area 32 at which there is secured to the housing an insulated holder. 33 carrying one element, in the form of a split metal pin 34, of a plug-and-soclretv coupling. The holder, 33 is located angularly by a spring pin 35 or.similar device and is secured in place by means of a ring 36 which engages a flange 31 on the holder and which is secured tothe housingby screws 38. The metalpin 34 is formed with a head'39 adapted to make a screw-threaded engagement with the insulated holder 33, a shoulder 49 on the pin beingarranged to abut on an interior end wall of the holder. The head 39 of the pin extends into a short stub 41 arranged to project through an aperture 42 in the porcelain tube 28 and crimped to the end of theleading-in wire i9.

The socket. member. of. the plug-and-socket coupling comprises a nickel core to which is soldered the end of. a cable 5i. The core 50 is located within crimped and soldered to a plug 53 offibrous. insulating material and'the free endsoffthe plug and core are surrounded by a hollow retaining cap 54 of fibrous insulated material secured by pins 55 to the plug 53. The pin holder 33 is formed (as shown in Figure 2) with a skirt 56, the external wall of which is screw-threaded for engagement by a metal nut 51 which has a flanged end 53 adapted to engage over the corresponding end of the retaining cap 54. By means of the nut 51 the plug-and-socket coupling may be securely held in the locked position, while by looseningof the nut, uncoupling is permitted, The cap 54 has a boss 59 which is arranged to surround the cable 5| at a position adjacent to the retaining cap 54. The cap 54 is split, one half I59 being removable and the two halves are held together by wire rings I60.

The-foregoing arrangement provides for the dissipation of heat by the metal housing, the.

expansion of the lamp in use, the etife t e nsulation of the leading-in wire and the safe and ready disconnection of the device from the source of electrical supply.

The arrangement shown in Figure 5 provides for the attachment of the plug-and-socket coupling to the-part ll of the housing in a position in line with the housing. This attachment is effected by means of an angle fitting 59, 6|, one arm 60 of which is arranged to be secured by screws 52 to the wall of the housing while the other arm 51 is arranged to encircle the flange 31 of. the pin holder 33. The arm 59 of the anglefltting carriesan asbestos plug 53 arranged to fit into the opening in the wall of the housing and the adjacent opening 42 in the wall of the porcelain tube.

I claim:

1. For use in combination with an electric lamp of the type described having a transparent vitreous. envelope at opposite ends of which leadingin wires, fused to the wall of the envelope, extend outwardly therefrom, an external end-connection and support for the lamp comprising an elongated tubular metal housing having one end part surrounding the body portion of the lamp atthe end thereof and an opposite end part surrounding the corresponding leading-in wire, a ring-like circumferentially expansible clamp secured to the housing within the first-mentioned part thereof and shaped to surround and engage the vitreous envelope of the lamp providing for its free circumferential expansion during operation,. a sleeve of heat-resisting electrically-insulating material located within the secondmentionedpart of the housing and providing an air-space enclosure within which the aforesaid leading-inwire is freely accommodated, and a plug-and-socket coupling comprising an insulated holder detachably connected to the seccud-mentioned part of the housing and a contact element carried by the holder and electrically connected to the leading-in wire aforesaid.

2. An external end connection and lamp support as claimed in claim 1 in which the outside wall of the aforesaid part of the housing surrounding the leading-in wire is formed with a flat to which is attached. in a direction at right anglesto the bore of the housing, the insulated holder which as aforesaid carries a contact element of the plug-and-socket coupling.

3. An external end connection and lamp support as claimed in claim 1 in which the aforesaid part of. the housing surrounding the leading-in wire is stepped down in diameter and eccentrically disposed inrelation to the other part of the housing, an internal flange beingformed at the Junction between the two housing parts, and the aforesaid ring-like expansible clamp being secured to said flange.

JOHN WILLIAM EASTER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,799,352 Buttolph Apr. 7, 1931 1,838,508 Wantz Dec. 29, 1931 1,963,964 Barclay June 26, 1934 2,160,648 de Jong et al May 30, 1939 2,488,065. Peterson Nov. 15, 1949 FOREIGN PATENTS Number Country Date 502,069. GreatBritainuuu Mar. 10, 1939 

